Endoscopists have developed great expertise in using elongate needles, including echogenic needles viewable under ultrasound, to obtain samples from patients in a minimally invasive manner. In particular, they use devices and techniques that allow carefully targeted collection of samples from deep in patient bodies without any external percutaneous incisions or punctures. Devices such as fine needle aspiration needles and fine needle biopsy needles may be directed through a working channel of an endoscope (e.g., duodenoscope, gastrointestinal end-viewing endoscope) to a target site in a patient body.
In order to obtain useful samples of tissue suitable for histological and/or cytological analysis, it is desirable to use a large-gauge needle. However, these needles are often considered stiff and unwieldy by some users who find them difficult to insert fully into, for example, a working channel of an endoscopic ultrasound (EUS) endoscope. In addition, as these needles typically include an outer sheath, it may be difficult to advance the penetrating/collecting distal end portion through and out of the sheath. These challenges may be particularly problematic when a user is attempting to access more difficult-to-reach anatomical locations (such as, for example, attempting to access the head of a patient's pancreas from the duodenum).
It would therefore be advantageous to provide a needle that includes a distal end dimensioned to collect samples of a desirable size while also providing a shaft proximal of that distal end that obviates the present difficulties of advancement and navigation through an endoscope working channel and through patient anatomy. The shaft provided should still provide desirable pushability and trackability so that the needle will be navigable in a manner consistent with the desires and aims of users to accurately obtain samples.